The invention relates to a cell for gas analyzers, having a casing with a cylindrical bore divided by an axial dividing wall into two chambers, the one being provided for the gas being measured and a measuring light beam, and the other for a reference medium and a reference light beam, and having windows on both sides, through which the measuring and reference light beams can pass.
A cell of this kind is disclosed by German publication DE-OS 30 10 516, and its use in a gas analyzer is described in DE-OS 27 20 636. A complete apparatus of this type is also disclosed in U.S. Pat. No. 4,101,221 - Schunck et al.
Whereas known cell is suitable for operating temperatures up to about 350.degree. C., it is not, however, suitable for the analysis of corrosive gases at high pressures (e.g., 40 bar), and at a high temperature relative to these pressures (e.g. 150.degree. C.).
In the known cell, only a reference gas is in the one chamber and only the gas being measured is in the other. Each chamber is provided with two connecting tubes, so that the known cell requires a total of four connections. The gas being measured unavoidably draws impurities into the one chamber, where some of them are precipitated and affect the transmission of the windows in the course of time. This simulates a change in the absorption of the gas being measured, which can lead to errors of measurement. Calibrating the analyzer before the measurement makes possible only a very limited compensation for this.
It is the object of the invention to improve a cell of the kind described above such that it can be used also at high pressures and for the analysis of corrosive gases at higher temperatures.